The BLM Tucson Field Office manages more than 600,000 acres in Gila, Pima, Pinal, Santa Cruz and Cochise counties in southeastern Arizona, and shares the international border with Mexico. Public lands in the field office include eight National Landscape Conservation System units: San Pedro Riparian National Conservation Area (RNCA), Las Cienegas National Conservation Area, the Ironwood Forest National Monument, four wilderness areas and 63 miles of river suitable for Wild and Scenic River Designation. The Tucson Field Office also oversees six properties under the National Register of Historic Places and seven Areas of Critical and Environmental Concern. The San Pedro RNCA is recognized as a globally significant bird area and attracts birders from all over the world who come to see some of the more than 400 birds found here.